Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive behavior, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the data provenance (Hyperliquid prediction markets), an apparent per-call cost of $0.005, and the returned fields (24h change, volume, decision date).

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence that leads with the resource and cost before enumerating the return fields. Dense but readable; the parenthetical is the only slightly awkward element.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the burden of describing the return payload, and it does so by naming the probabilities, 24h change, volume and decision date. It is close to complete for a zero-parameter read tool, though the exact response structure remains only partially specified.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The description correctly implies the tool is invoked without arguments.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific resource (Fed rate decision odds for the next FOMC and other central-bank decisions) and its source (Hyperliquid prediction markets), plus the shape of the answer (cut/no-change/hike probabilities). It does not explicitly differentiate itself from potentially overlapping siblings such as markets.prediction or macro.calendar, so it stops short of a 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied: an agent can infer this is the tool for Fed/central-bank rate odds, but the description never states when to prefer it over macro.calendar or markets.prediction, nor any exclusion or prerequisite. Adequate but with a clear routing gap.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.